Encouraging results have recently emerged regarding a new vaccine which suggests that with continued development the elimination of cervical cancer could be on the cards.
The new vaccine targets the human papillomavirus (HPV). Since HPV can cause cervical cancer, research has shown how the replacement of the current anti-HPV vaccines with a newer vaccine could lead to broader protection against all 15 cancer inducing HPV types.
Scientists have discovered that the L2 protein, a minor constituent of the virus, is the same across all HPV strains. Therefore researchers have proposed that, in vaccines where this protein is the main component, a range of antibodies would become active against many HPV types, leading to greater levels of cervical cancer prevention being achieved.
As it stands, Cervarix and Gardasil, produced by the pharmaceutical companies GlaxoSmithKline and Merck & Co. respectively are the only anti-HPV vaccines currently available. The protein L1 is the main vaccine component in both. L1 proteins form a major part of the virus and differ in each HPV strain. Since existing vaccines are made up of L1 proteins from just HPV 16 and 18, the current protection is specific against only these types. Although these two strains have been attributed to 70% of cervical cancer cases, Cervarix and Gardasil’s targeting of these two types only causes a void to remain where cancer can still be induced by the 13 other cancerous non-vaccine strains.
Whilst these current vaccines have been significant milestones for working towards cervical cancer control, the move towards vaccines which instead contain L2 proteins could be pivotal for progression further down this path.
Since cervical cancer has been classified as one of the top three most common cancers in women in the developing world, as compared to 11th in the UK, many are naive to the extent of HPV’s global impact. The lack of healthcare infrastructure and financial resources in many countries impedes widespread vaccination coverage whereby the sparse availability of cervical screening acts as ‘the final straw’ to exasperate the number of cases. The worldwide annual death toll from cervical cancer has been estimated by the World Health Organisation to exceed 275,000 and predicted only to rise in the next decade. This anticipated increase serves as a time bomb to enhance the importance of the quest to develop an inexpensive anti-HPV vaccine.
Fortunately the use of vaccines which contain L2 proteins instead of L1 look to be the solution for
this cost issue. As well as having the potential to confer protection against many HPV strains, the L2 vaccines are able to be produced cheaply using bacteria resulting in an overall production cost significantly less than the manufacturing cost of both Cervarix and Gardasil. This therefore would favour greater vaccination coverage amongst developing nations.
In recent years increasingly concentrated efforts have been put into scientific trials to explore the new anti-HPV vaccines where the successes from these trials have made the prospects for the L2 vaccination look bright. Under particular scrutiny is the L2 protein itself. Scientists have engaged into experimentation to conclude that when vaccines contain just a particular region of the L2 protein they are most effective at evoking antibodies which are protective against a range of HPV’s. The induction of a weaker immune response compared to that induced by the current anti-HPV vaccines has so far been the only negative observation detected. Thus scientists are delving into this area further to probe which parts of the L2 protein should be used so that the vaccine gives lifelong protection against HPV in a cost effective manner.
However, whilst the quandary of the L2 vaccination inducing a weak immune response remains, vaccination with Cervarix and Gardasil continues as the sole method of conferring protection against certain cancer inducing HPV strains. Despite only providing protection against two HPV types, if strict coherence to the recommended vaccination and screening schedule is obeyed the likelihood of a contracted HPV infection going unnoticed and progressing to cervical cancer is slim. Therefore, although L2 vaccines show signs of being the gold standard for the achievement of cervical cancer prevention, the existing anti-HPV vaccines should not be underestimated and their use certainly not boycotted.
Nevertheless the world should hold its breath in the hope of further developmental success concerning L2 vaccines as, if progress in this area continues, people may one day awaken to the dream of cervical cancer elimination being a reality.